Electrical switch assembly



R. w. FRASER ELECTRICAL SWITCH ASSEMBLY Fileq July 7, 1960 June 4, 1963 1713137413502 R0222"? W Fvtaser, .9 9... 5 1 JR? United States Patent 3,092,703 ELECTRICAL SWI-ITQH ASSEMBLY Robert W. Fraser, Framingham, Mass, assignor to United- Carr Fastener Corporation, Cambridge, Mass a corporation of Delaware Filed July 7, 1960, Ser. No. 41,385 2 Claims. (Cl. 200-159) This invention relates in general to an improved switch assembly and the method of installing a freely rotatable contact therein.

Heretofore switch mechanisms for use in the automotive and appliance industries have utilized non-rotatable contacts secured firmly to the switch housing and which make and break at the same points over a period of operation. Consequently, considerable carbon deposits resulting from frequent and unavoidable arcing has resulted in switch failure. Various types of contact assemblies have been tried to change the area of electrical connection and minimize the possibilities of switch non-functions.

The object of this invention is to provide a switch having a free floating loosely assembled terminal contact.

A further object of this invention is to provide a method of assembling a loosely held terminal contact within a switch body.

Other objects of the invention will, in part, be obvious, and will, in part, appear hereinafter.

In the drawing:

FIG. 1 is a top plan view of the switch;

FIG. 2 is a view in side elevation of the switch assembly;

FIG. 3 is a bottom plan view of the switch;

FIG. 4 is a View in section taken on line 44 of FIG. 2;

FIG. 5 is an enlarged view in section taken on line 55 of FIG. 2;

FIG. 6 is a view in section of the switch assembly with the plunger cap removed and a contact assembly tool positioned therein;

FIG. 7 is an isometric view of the cap portion of the switch.

Referring to the drawings, there is illustrated a switch assembly 10 adapted for mounting in a panel and retention therein by serrated snap fastener 12.

The switch assembly 10 includes a flange 14 having a central aperture 16 therein and a hollow elongated plunger 18 biased in the direction of the flange by a spring member 20. The spring is retained in assembly by an annular flange 22 formed on the plunger and disposed intermediate the distal ends 24 and 26 of the plunger and an inwardly curled cup 27 formed on the end 28 of the snap fastener 12 opposite to the flange \14. The plunger barrel 18 has an internal lip 30 formed thereon spaced from one end 26 for a purpose to be described hereinafter. The opposite end 24 of the plunger 18 has a chamferred connterbore 36 terminating in an undercut 38 adapted to cooperate upon snap engagement with a cap portion 40 having a flared end 42 and separated from the cap by a reduced neck 44 to complete the plunger assembly. A terminal contact member 46 includes a rolled tubular eyelet having a cup shaped flange 48 at one end and a pair of detents 50 and 52 formed on the interior or" the barrel and spaced inwardly from the flange 48. The detents 50 and 52 cooperate with a male contact (not shown) supplying electrical energy to the switch.

The assembly of the terminal contact member 46 onto the plunger barrel 18 as illustrated in FIG. 6 constitutes an improvement in this type of switch. The cup shaped flange 48 is inserted over the end 26 of the plunger barrel 1'8 with the contact 46 extending upwardly into the barrel. A curling tool 54 is then inserted down through the hollow plunger 18 and axial pressure applied which causes the open end 56 to flare over the internal lip 30. The overall length of the contact 46 is greater than the distance between the internal lip 30 and the distal end 26 of the plunger, thereby allowing the contact when assembled with the plunger to be freely rotatable. The assembly is completed by snapping the cap portion 40 into the chamferred counterbore so that the flared end 42 cooperates with the undercut 38.

It will be readily seen by anyone skilled in the art that by utilizing a two piece plunger construction, the assembly of the contact with the plunger can be quickly and efliciently done with the added benefits of allowing rotation of the contact with respect to the remainder of the switch.

Since certain other obvious modifications may be made in the device without departing from the scope of the invention, it is intended that all matter contained herein be interpreted in an illustrative and not in a limiting sense.

I claim:

1. A switch assembly adapted to be snapped into a support and having an axially operable plunger, said switch assembly including an elongated snap fastener having a flange at one end, said plunger assembled within said snap fastener and having a portion extending through an aperture in said flange, said plunger also extending through and beyond an opposite end of said snap fastener spaced from said flanged end, said plunger being of a dimension to pass freely through said snap fiastener and being assembled with the snap fastener only by a coil spring member interposed between a shoulder on the plunger and a portion of the snap fastener and a terminal contact member having a flange fitting over an end of the plunger adjacent to said opposite end, and an eyelet portion extending into said plunger and curled against an internal lip in the plunger.

2. A switch assembly adapted to be snapped into a support and having an axially operable plunger, said switch assembly including an elongated snap fastener having a flange :at one end, said plunger assembled within said snap fastener and having a portion extending through an aperture in said flange, said plunger also extending through and beyond an opposite end of said snap fastener spaced from said flanged end, said plunger being of a dimension to pass freely through said snap fastener and being assembled with the snap fastener only by a coil spring member interposed between a shoulder on the plunger and a portion of the snap fastener and a terminal contact member having a flange fitting over an end of the plunger adjacent to said opposite end, and an eyelet portion extending into said plunger and curled against an internal lip in the plunger, said plunger having a removable cap portion at that end opposite the end carrying the contact terminal for the purpose described.

References Cited in the file of this patent UNITED STATES PATENTS 1,699,491 Miller Jan. 15, 1929 2,605,374 Batcheller July 29, 1952 2,646,613 Enzler July 28, 1953 2,717,296 Foley et a1. Sept. 6, 1955 2,739,369 Cooney Mar. 27, 1956 2,759,074 Pettit Aug. 14, 1956 

1. A SWITCH ASSEMBLY ADAPTED TO BE SNAPPED INTO A SUPPORT AND HAVING AN AXIALLY OPERABLE PLUNGER, SAID SWITCH ASSEMBLY INCLUDING AN ELONGATED SNAP FASTENER HAVING A FLANGE AT ONE END, SAID PLUNGER ASSEMBLED WITHIN SAID SNAP FASTENER AND HAVING A PORTION EXTENDING THROUGH AN APERTURE IN SAID FLANGE, SAID PLUNGER ALSO EXTENDING THROUGH AND BEYOND AN OPPOSITE END OF SAID SNAP FASTENER SPACED FROM SAID FLANGED END, SAID PLUNGER BEING OF A DIMENSION TO PASS FREELY THROUGH SAID SNAP FASTNER AND BEING ASSEMBLED WITH THE SNAP FASTENER ONLY BY A COIL SPRING MEMBER INTERPOSED BETWEEN A SHOULDER ON THE PLUNGER AND A PORTION OF THE SNAP FASTENER AND A TERMINAL CONTACT MEMBER HAVING A FLANGE FITTING OVER AN END OF THE PLUNGER ADJACENT TO SAID OPPOSITE END, AND AN EYELET PORTION EXTENDING INTO SAID PLUNGER AND CURLED AGAINST AN INTERNAL LIP IN THE PLUNGER. 